All Questions
18
questions
12
votes
6
answers
5k
views
Ripple voltage filtering capacitor
I'm an self-taught high schooler who's trying to understand how filtering capacitors work. I've searched and read multiple websites trying to understand how filtering works. At the point where I am, I'...
- 311
7
votes
1
answer
13k
views
Ripple reduction with LC filter
This seems like it must be a common problem but I don't find a clear answer anywhere, maybe my approach is wrong.
I have a DC-DC regulator in my circuit, which has a ripple of 50mV at 200kHz, the ...
- 71
7
votes
3
answers
112k
views
Full-wave bridge rectifier with capacitor filter and ripple voltage
According to various sources, the ripple voltage of a full-wave bridge rectifier is
$$ V_r = \frac{V_s}{2}fCR $$
where \$V_s\$ is the peak of the input voltage source, \$f\$ is the frequency, \$C\$ ...
- 1,015
5
votes
3
answers
1k
views
Ripple rejection of capacitance multiplier when compared to linear regulators
There are some posts and discussions how a circuit popularly called a “capacitance multiplier” could reduce low frequency ripple noise (at 50/60 Hz or 100/120 Hz) and could perform better than common (...
- 1,589
3
votes
1
answer
2k
views
Sanity check: Input and output filter for a stacked pair of DC/DC converters
In my current project, I need voltages of +/- 30V and +/- 15V for analog control purposes. The current on the 30V rails is fairly limited, ca. 70mA max on one rail and <10mA on the other. The 15V ...
- 607
1
vote
1
answer
3k
views
Pi filter design for SMPS output ripple
Given a circuit like a buck-converter like the AOZ1284PI in a circuit such as this one:
Or push-pull converters such as this one:
If one was to design at the output a low-pass PI filter with a ...
- 469
1
vote
3
answers
2k
views
Vdc in ripple factor
V_p(rect) is the rectified unfiltered peak voltage
V_r(pp) is the peak-to-peak voltage after filtering by a capacitor
Here is a picture:
V_r(pp) is given by the expression:
Which I have no problem ...
- 161
1
vote
1
answer
739
views
How to calculate voltage ripple in a BLDC filter module?
Hi
I need some calculation for my thesis. A found this picture on the internet. My project is almost the same.
It's a pi filter for a 3 phase BLDC. The peak current is 60A. It runs from 12V car ...
- 77
1
vote
3
answers
2k
views
Running 9v battery in parallel with Power Supply
I am putting a 9v powered circuit into an electric guitar. It will be powered by a 9v power supply through a cable, and also have a backup 9v battery on board the guitar. I am wondering if I could run ...
- 19
0
votes
1
answer
57
views
LC Filter Creates Ripple Voltage in Buck Converter
I'm currently designing a synchronous buck converter and trying to simulate it in LTSpice.
I know the purpose of L1 and C4 is to act as a filter to smooth out the output, since it would be rapidly ...
0
votes
2
answers
62
views
Why do I get a different value for DC output?
I am given the circuit shown below, a full wave rectifier with a filter.
To find the DC output on a full wave rectifier with a filter, I was given the formula:
$$V_{dc}(out) = \frac{V_{M}}{1+\frac{1}{...
- 97
0
votes
1
answer
964
views
Designing a pi filter (C-L-C) for the output of a TPS62740 buck converter
We are using a TPS62740 IC as DC-DC converter.
We are getting ripple at the output in the range of 10 mV to 12 mV, so we are thinking to add a pi (C-L-L) filter at the output of the DC-DC converter.
...
0
votes
1
answer
470
views
How to protect constant LED current from ripples & clamps?
I need to develope a constant current LED Driver. The product must be portable and as small as possible. So I can not use SMPS, I have use AC/DC adapter as source. This is the AC/DC adapters output:
...
- 1,313
0
votes
1
answer
387
views
How to remove 200 mV ripple from my power supply? [closed]
I am using a step-down-converter to get a variable supply output in the range of 2-4 V from a 5 V input voltage from an adapter.
The problem I am facing is that I get a 200 mV ripple which looks like ...
- 65
0
votes
0
answers
55
views
Proof of ripple voltage of capacitor filter?
From Electronic Devices and Circuit Theory by Robert L. Boylestad:
To get an equation for ripple voltage, the book wrote, $$\frac{V_{r(p-p)}}{T_1}=\frac{V_m}{\frac{T}{4}}$$
How did they come up with ...
- 1